Lifting device with swinging arms

ABSTRACT

The device comprises two arms B and C articulated to each other by means of pivot 3 and the outer ends of said arms are retained respectively by a base frame E and by the ends of platform D. Furthermore, said arms are combined with counterweights 4 and 5 which perform a swinging motion around pivot 2 which connects said arms to base-frame E. The first counterweight 4 is retained by the first arm, whereas the second counterweight 5 is actuated by the swinging motion of the second arm by means of transmission members 7 and 14.

United States Patent [1 1 Levrini [451 July 3,1973

[ LIFTING DEVICE WITH SWINGING ARMS [76] Inventor: Tullio Levrinl, Via Turati 26, Milan,

Italy [22] Filed: July 20, 1971 [21] Appl. No.: 164,334

[30] Foreign Application Priority Data July 29, 1970 Italy 28039 A/7O [52] U.S. Cl 182/2, 212/59, 212/49 [51] Int. Cl. E04g 1/00 [58] Field of Search 212/58, 59,48, 49; 182/2; 137/615 [56] References Cited UNITED STATES PATENTS 3,073,343 1/l963 Mowell l37/6l5 3,362,432 l/l968 Jameson [37/615 3,l08,656 l0/l963 Asplundh 182/2 3.434.497 3/1969 Bily l37/6l5 FOREIGN PATENTS OR APPLICATIONS 249,126 9/l96l Australia l37/6l5 Primary E.ramirler-Harvey C. Hornsby Attorney-Harold T. Stowell et al.

[57 ABSTRACT The device comprisestwo arms B and C articulated to each other by means of pivot 3 and the outer ends of said arms are retained respectively by a base frame E and by the ends of platform D. Furthermore. said arms are combined with counterweights 4 and 5 which perform a swinging motion around pivot 2 which connects said arms to base-frame E. The first counterweight 4 is retained by the first arm, whereas the second counterweight 5 is actuated by the swinging motion of the second arm by means of transmission members 7 and 14.

11 Claims, 3 Drawing Figures PAIENTEDJUL3 ms 3. 743.049

INVENTOR TULLlD LEV R\N| ATTORNEYS LIFTING DEVICE WITH SWINGING ARMS This invention concerns a device provided with swinging arms.

There are several well known lifting devices with swinging arms, particularly designed for working, maintenance, first-aid operations and the like. Such means have to be equipped with tough bearing arms which rest on the ground, in order to prevent the device'from collapsing.

The production cost of said devices is high and they are slow to operate and even dangerous, due to a possible collapse of the bearing structure. Furthermore, when said known lifting devices are on operation, it is impossible to move the vehicles to be lifted.

The purpose of the present invention is to obviate the above mentioned and other drawbacks.

The device according to the invention is substantially characterized in that it comprises a first swinging arm, supported in such a way that the axis thereof is substantially horizontal with respect to the base body of the device and said arm is provided with a counter-weight to balance, at least in part, the weight which bears on said arm. The device of the present invention is further characterized in that is is provided with a second swinging arm (with the axis thereof extending in a substantially horizontal direction) linked, by means of an articulated joint, to the outer end of the first swinging arm, said second swinging arm being balanced, at least in part, by means of a secound counter-weight connected, by means of an articulated joint, to the oscillating axis of the first swinging arm, said counterweight being connected to the second swinging arm by means of transmitting members, in such a way as to establish the desired univocal angular position of the second counterweight with respect to the base body of the lifting device.

In the drawing:

FIG. 1 is an elevational view of the device.

FIG. 2 is a plan view of-the second arm.

FIG. 3 is a plan view of the device without the second arm (i.e. with the second arm broken ofi).

One shaft 2, having a horizontal axis, is connected to the two sides 1 and the first arm B idles on said shaft. The free end of said arm B is articulated to the second arm C by means of shaft 3 which is integral with arm B. Arm B supports a counterweight 4, at the side opposite to pivot 3.

Two counterweights 5 which are idling on shaft 2, are connected by means of two wheels 6 and two chains 7, to chain-wheels 8 integral with arm C. Counterweights 5 (wheels 6 and 8 having the same diameter) rotate at the same angles as arm C. Arm C supports, at its outer end, cabin D (for persons and objects) which swings around pivot 9. Said oscillation is controlled by means of one chain 10 which winds onto a wheel 11 (integral with cabin D) and onto a wheel 12 which idles around axis 3 and which is integral with a second wheel for chain 14 which winds, in turn, onto chain wheel 15 which is co-axial with shaft 2 and integral with said shaft. In such a way, wheels 11, I2, 13 and 15 having the same diameter, cabin D is constantly orientated in the same direction, whichever the angle of inclination of arms B and C may be.

The device of the present invention is complete with a base frame 4 which can be equipped with supporting and steering wheels; or else (as shown inthe illustrated example), with three or four wheels 16 which are orientated in such a way that they are allowed to rotate in a circular guide 17. In such case, since at least one of wheels 16 must be allowed to rotate (for example with a hydraulic motor 18), it is possible to vary the angular position of the device with respect to vertical axis XX.

The swinging motion of the first arm B is realized by means of a hydraulic cylinder 19 and the oscillation of the second arm C is realized by means of a hydraulic cylinder 20 integral with arm B and which acts on chains 7 (or otherwise by means of a hydraulic cylinder which acts directly between arms B and C). Arm C can be operated. as well by members integral with frame IE (not with arm B) and which members act on counterweight 5 or, otherwise, on chains 7. In this case, since only arrn B is operated, the orientation of arm C with respect to base E remains constant. Pivot 21 of cylinder 19 can be moved, to fit into hole 22 of arm B, whenever this is desired, in order to realize a further angle of scillation of arm B.

The weight of the counter-weights can be selected in different ways, as follows:

EXAMPLE I Couterweights designed to balance their own weights only. The capacity required is that which corresponds only to the lift of the useful load which is contained in the cabin D (persons and/or objects).

EXAMPLE 2 Counterweights to balance their own weights plus the useful weight contained in the cabin. The capacity required for the motion is almost zero; dumping unbalance: zero.

To obtain the above mentioned condition it is necessary to adjust the counterweights whenever the loads in the cabin are altered (either by varying the value of said counterweights and/or by varying the center-ofgravity of said counterweights, for instance by adding supplemental compound weights and/or by moving weights 4 and 5 away from the axis of oscillation 3 and- /or by approaching said weights to said axis).

It is further possible to ballast the cabin by means of removable weights 23, i.e. by withdrawing a certain number of said weights 23, according to the increase in weight of the load contained in the cabin.

EXAMPLE 3 Counterweights required to balance their own weight, plus half of the maximum allowable weight in the cabin.

It is, of course, possible to make use of balancing values which are different from the above described values. If the necessary capacity is small, then it is possible to realize a hand-operated device (which is operated from the ground and/or from the cabin), for example by means of hand-pumps or endless screws, etc. Frame E can be integral with the trolley (not shown) which, thanks to its steering wheels, can move, i.e. orientate the arms as desired around the vertical axis XX. (In this case elements 16 and 17 are absent).

The controls to operate, to stop and to steer the carriage can be arranged in cabin D, together with the controls for the swinging motion of the arms. It is possible to substitute the hydraulic control for the arms with electric motors and reduction gears (for instance of the type with endless screw and helicoidal wheel) and by limiting the swinging angle of arm C with respect to arm B, whereas chains 7 can be substituted with one or several rods.

What we claim is:

1. A swinging arm type lifting device comprising a base member, a horizontal cross shaft carried by said base member, a first swinging arm, means pivotally mounting said first swinging arm intermediate its length to said cross shaft, a counter-weight carried at one end of said shaft first swinging arm, said counter-weight being sized to balance at least in part weight which bears on the other end of said first swinging "arm, a second swinging arm, means pivotally mounting said second swinging arm to the other end of the first swinging arm on an axis parallel to the axis of the cross shaft, second counter-weight means balancing at least in part the said second swinging arm, said second counterweight means being pivotally mounted on said cross shaft, and force transmission means connecting the second counter-weight and said second swinging arm to establish the angular position of the second counterweight in respect to the angular position of the second swinging arm and the base member, independent drive means for pivoting the first swinging arm about the cross shaft and for pivoting the second swinging arm about its pivotal connection to the first swinging arm, a cabin, means pivotally mounting the cabin to the free end of the second swinging arm, and control means associated with the pivotal axis between the first and second swinging arms and the first swinging arm and the base member to maintain orientation of said cabin,

2. A device as claimed in claim 1, characterized in that the drive means for the second swinging arm is realized by means linked to the first swinging arm.

3. A device as claimed in claim 1, characterized in that the motion of the second swinging arm is obtained by means linked to the base member.

4. A device according to claim 1 including a hydraulic cylinder to drive the first swinging arm, said hydraulic cylinder having two different points of connection with the said first swinging arm, in order to realize an increase in the angle of oscillation of said first swinging arm.

5. A device according to claim 1, characterized in that the counterweights are so dimensioned as to substantially balance the weight of the swinging arm members only.

6. A device according to claim 1, characterized in that the counterweights are so dimensioned as to substantially balance their own weight, plus approximately one half of the maximum load allowed in the cabin.

7. A device as claimed in claim 1, characterized in that the counterweights are so dimensioned as to balance their own weight, plus the maximum load allowed in the cabin.

8. A device as claimed in claim 1, characterized in that the counterweights can be adjusted at least in part, both as regards the value thereof and the distance of their center of gravity from the axis of oscillation.

9. A device as claimed in claim 1, characterized in that the cabin is provided with removable ballast means, in order to realize the desired balance.

10. A device as claimed in claim 1, characterized in that the base member is mounted on supporting wheels, to rotate the device around the vertical axis thereof.

11. A device as claimed in claim 1, characterized in that the motion of the arms is realized by means of hydraulic cylinders and associated hand-pumps. 

1. A swinging arm type lifting device comprising a base member, a horizontal cross shaft carried by said base member, a first swinging arm, means pivotally mounting said first swinging arm intermediate its length to said cross shaft, a counter-weight carried at one end of sAid shaft first swinging arm, said counter-weight being sized to balance at least in part weight which bears on the other end of said first swinging arm, a second swinging arm, means pivotally mounting said second swinging arm to the other end of the first swinging arm on an axis parallel to the axis of the cross shaft, second counter-weight means balancing at least in part the said second swinging arm, said second counter-weight means being pivotally mounted on said cross shaft, and force transmission means connecting the second counter-weight and said second swinging arm to establish the angular position of the second counter-weight in respect to the angular position of the second swinging arm and the base member, independent drive means for pivoting the first swinging arm about the cross shaft and for pivoting the second swinging arm about its pivotal connection to the first swinging arm, a cabin, means pivotally mounting the cabin to the free end of the second swinging arm, and control means associated with the pivotal axis between the first and second swinging arms and the first swinging arm and the base member to maintain orientation of said cabin.
 2. A device as claimed in claim 1, characterized in that the drive means for the second swinging arm is realized by means linked to the first swinging arm.
 3. A device as claimed in claim 1, characterized in that the motion of the second swinging arm is obtained by means linked to the base member.
 4. A device according to claim 1 including a hydraulic cylinder to drive the first swinging arm, said hydraulic cylinder having two different points of connection with the said first swinging arm, in order to realize an increase in the angle of oscillation of said first swinging arm.
 5. A device according to claim 1, characterized in that the counterweights are so dimensioned as to substantially balance the weight of the swinging arm members only.
 6. A device according to claim 1, characterized in that the counterweights are so dimensioned as to substantially balance their own weight, plus approximately one half of the maximum load allowed in the cabin.
 7. A device as claimed in claim 1, characterized in that the counterweights are so dimensioned as to balance their own weight, plus the maximum load allowed in the cabin.
 8. A device as claimed in claim 1, characterized in that the counterweights can be adjusted at least in part, both as regards the value thereof and the distance of their center of gravity from the axis of oscillation.
 9. A device as claimed in claim 1, characterized in that the cabin is provided with removable ballast means, in order to realize the desired balance.
 10. A device as claimed in claim 1, characterized in that the base member is mounted on supporting wheels, to rotate the device around the vertical axis thereof.
 11. A device as claimed in claim 1, characterized in that the motion of the arms is realized by means of hydraulic cylinders and associated hand-pumps. 